Reland: Multiview pipeline (#47234)

This PR relands #44473.

The previous PR was immediately reverted after merging because we found that the PR could cause illegal renders to be skipped on debug builds but crash the app on release builds. This PR makes the `Animator::Render` skip illegal renders as well. This should not be the final shape of this feature, and thus a TODO is added.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

Author: dkwingsmt

flow/frame_timings.cc

@@ -254,8 +254,30 @@ const char* FrameTimingsRecorder::GetFrameNumberTraceArg() const {
   return frame_number_trace_arg_val_.c_str();
 }
 
+static const char* StateToString(FrameTimingsRecorder::State state) {
+#ifndef NDEBUG
+  switch (state) {
+    case FrameTimingsRecorder::State::kUninitialized:
+      return "kUninitialized";
+    case FrameTimingsRecorder::State::kVsync:
+      return "kVsync";
+    case FrameTimingsRecorder::State::kBuildStart:
+      return "kBuildStart";
+    case FrameTimingsRecorder::State::kBuildEnd:
+      return "kBuildEnd";
+    case FrameTimingsRecorder::State::kRasterStart:
+      return "kRasterStart";
+    case FrameTimingsRecorder::State::kRasterEnd:
+      return "kRasterEnd";
+  };
+  FML_UNREACHABLE();
+#endif
+  return "";
+}
+
 void FrameTimingsRecorder::AssertInState(State state) const {
-  FML_DCHECK(state_ == state);
+  FML_DCHECK(state_ == state) << "Expected state " << StateToString(state)
+                              << ", actual state " << StateToString(state_);
 }
 
 }  // namespace flutter

flow/frame_timings.h

@@ -31,6 +31,7 @@ class FrameTimingsRecorder {
  public:
   /// Various states that the recorder can be in. When created the recorder is
   /// in an unitialized state and transtions in sequential order of the states.
+  // After adding an item to this enum, modify StateToString accordingly.
   enum class State : uint32_t {
     kUninitialized,
     kVsync,
@@ -121,6 +122,8 @@ class FrameTimingsRecorder {
   ///
   /// Instead of adding a `GetState` method and asserting on the result, this
   /// method prevents other logic from relying on the state.
+  ///
+  /// In opt builds, this call is a no-op.
   void AssertInState(State state) const;
 
  private:

impeller/entity/contents/filters/gaussian_blur_filter_contents.cc

@@ -26,8 +26,8 @@ namespace impeller {
 DirectionalGaussianBlurFilterContents::DirectionalGaussianBlurFilterContents() =
     default;
 
-DirectionalGaussianBlurFilterContents::
-    ~DirectionalGaussianBlurFilterContents() = default;
+DirectionalGaussianBlurFilterContents::~
+DirectionalGaussianBlurFilterContents() = default;
 
 void DirectionalGaussianBlurFilterContents::SetSigma(Sigma sigma) {
   blur_sigma_ = sigma;

lib/ui/dart_ui.cc

@@ -98,7 +98,7 @@ typedef CanvasPath Path;
   V(NativeStringAttribute::initSpellOutStringAttribute, 3)            \
   V(PlatformConfigurationNativeApi::DefaultRouteName, 0)              \
   V(PlatformConfigurationNativeApi::ScheduleFrame, 0)                 \
-  V(PlatformConfigurationNativeApi::Render, 1)                        \
+  V(PlatformConfigurationNativeApi::Render, 2)                        \
   V(PlatformConfigurationNativeApi::UpdateSemantics, 1)               \
   V(PlatformConfigurationNativeApi::SetNeedsReportTimings, 1)         \
   V(PlatformConfigurationNativeApi::SetIsolateDebugName, 1)           \

lib/ui/painting/image_dispose_unittests.cc

@@ -5,6 +5,7 @@
 #define FML_USED_ON_EMBEDDER
 
 #include "flutter/common/task_runners.h"
+#include "flutter/fml/synchronization/count_down_latch.h"
 #include "flutter/fml/synchronization/waitable_event.h"
 #include "flutter/lib/ui/painting/canvas.h"
 #include "flutter/lib/ui/painting/image.h"
@@ -57,6 +58,10 @@ TEST_F(ImageDisposeTest, ImageReleasedAfterFrameAndDisposePictureAndLayer) {
   };
 
   Settings settings = CreateSettingsForFixture();
+  fml::CountDownLatch frame_latch{2};
+  settings.frame_rasterized_callback = [&frame_latch](const FrameTiming& t) {
+    frame_latch.CountDown();
+  };
   auto task_runner = CreateNewThread();
   TaskRunners task_runners("test",                  // label
                            GetCurrentTaskRunner(),  // platform
@@ -83,12 +88,15 @@ TEST_F(ImageDisposeTest, ImageReleasedAfterFrameAndDisposePictureAndLayer) {
   shell->RunEngine(std::move(configuration), [&](auto result) {
     ASSERT_EQ(result, Engine::RunStatus::Success);
   });
-
   message_latch_.Wait();
 
   ASSERT_TRUE(current_display_list_);
   ASSERT_TRUE(current_image_);
 
+  // Wait for 2 frames to be rasterized. The 2nd frame releases resources of the
+  // 1st frame.
+  frame_latch.Wait();
+
   // Force a drain the SkiaUnrefQueue. The engine does this normally as frames
   // pump, but we force it here to make the test more deterministic.
   message_latch_.Reset();

lib/ui/window.dart

@@ -356,18 +356,20 @@ class FlutterView {
   void render(Scene scene) {
     // Duplicated calls or calls outside of onBeginFrame/onDrawFrame (indicated
     // by _debugRenderedViews being null) are ignored. See _debugRenderedViews.
+    // TODO(dkwingsmt): We should change this skip into an assertion.
+    // https://github.com/flutter/flutter/issues/137073
     bool validRender = true;
     assert(() {
       validRender = platformDispatcher._debugRenderedViews?.add(this) ?? false;
       return true;
     }());
     if (validRender) {
-      _render(scene as _NativeScene);
+      _render(viewId, scene as _NativeScene);
     }
   }
 
-  @Native<Void Function(Pointer<Void>)>(symbol: 'PlatformConfigurationNativeApi::Render')
-  external static void _render(_NativeScene scene);
+  @Native<Void Function(Int64, Pointer<Void>)>(symbol: 'PlatformConfigurationNativeApi::Render')
+  external static void _render(int viewId, _NativeScene scene);
 
   /// Change the retained semantics data about this [FlutterView].
   ///

lib/ui/window/platform_configuration.cc

@@ -449,9 +449,10 @@ void PlatformConfiguration::CompletePlatformMessageResponse(
   response->Complete(std::make_unique<fml::DataMapping>(std::move(data)));
 }
 
-void PlatformConfigurationNativeApi::Render(Scene* scene) {
+void PlatformConfigurationNativeApi::Render(int64_t view_id, Scene* scene) {
   UIDartState::ThrowIfUIOperationsProhibited();
-  UIDartState::Current()->platform_configuration()->client()->Render(scene);
+  UIDartState::Current()->platform_configuration()->client()->Render(view_id,
+                                                                     scene);
 }
 
 void PlatformConfigurationNativeApi::SetNeedsReportTimings(bool value) {

lib/ui/window/platform_configuration.h

@@ -69,7 +69,7 @@ class PlatformConfigurationClient {
   /// @brief      Updates the client's rendering on the GPU with the newly
   ///             provided Scene.
   ///
-  virtual void Render(Scene* scene) = 0;
+  virtual void Render(int64_t view_id, Scene* scene) = 0;
 
   //--------------------------------------------------------------------------
   /// @brief      Receives an updated semantics tree from the Framework.
@@ -557,7 +557,7 @@ class PlatformConfigurationNativeApi {
 
   static void ScheduleFrame();
 
-  static void Render(Scene* scene);
+  static void Render(int64_t view_id, Scene* scene);
 
   static void UpdateSemantics(SemanticsUpdate* update);
 

lib/ui/window/platform_configuration_unittests.cc

@@ -15,8 +15,166 @@
 #include "flutter/shell/common/shell_test.h"
 #include "flutter/shell/common/thread_host.h"
 #include "flutter/testing/testing.h"
+#include "gmock/gmock.h"
 
 namespace flutter {
+
+namespace {
+
+static constexpr int64_t kImplicitViewId = 0;
+
+static void PostSync(const fml::RefPtr<fml::TaskRunner>& task_runner,
+                     const fml::closure& task) {
+  fml::AutoResetWaitableEvent latch;
+  fml::TaskRunner::RunNowOrPostTask(task_runner, [&latch, &task] {
+    task();
+    latch.Signal();
+  });
+  latch.Wait();
+}
+
+class MockRuntimeDelegate : public RuntimeDelegate {
+ public:
+  MOCK_METHOD(std::string, DefaultRouteName, (), (override));
+  MOCK_METHOD(void, ScheduleFrame, (bool), (override));
+  MOCK_METHOD(void,
+              Render,
+              (int64_t, std::unique_ptr<flutter::LayerTree>, float),
+              (override));
+  MOCK_METHOD(void,
+              UpdateSemantics,
+              (SemanticsNodeUpdates, CustomAccessibilityActionUpdates),
+              (override));
+  MOCK_METHOD(void,
+              HandlePlatformMessage,
+              (std::unique_ptr<PlatformMessage>),
+              (override));
+  MOCK_METHOD(FontCollection&, GetFontCollection, (), (override));
+  MOCK_METHOD(std::shared_ptr<AssetManager>, GetAssetManager, (), (override));
+  MOCK_METHOD(void, OnRootIsolateCreated, (), (override));
+  MOCK_METHOD(void,
+              UpdateIsolateDescription,
+              (const std::string, int64_t),
+              (override));
+  MOCK_METHOD(void, SetNeedsReportTimings, (bool), (override));
+  MOCK_METHOD(std::unique_ptr<std::vector<std::string>>,
+              ComputePlatformResolvedLocale,
+              (const std::vector<std::string>&),
+              (override));
+  MOCK_METHOD(void, RequestDartDeferredLibrary, (intptr_t), (override));
+  MOCK_METHOD(std::weak_ptr<PlatformMessageHandler>,
+              GetPlatformMessageHandler,
+              (),
+              (const, override));
+  MOCK_METHOD(void, SendChannelUpdate, (std::string, bool), (override));
+  MOCK_METHOD(double,
+              GetScaledFontSize,
+              (double font_size, int configuration_id),
+              (const, override));
+};
+
+class MockPlatformMessageHandler : public PlatformMessageHandler {
+ public:
+  MOCK_METHOD(void,
+              HandlePlatformMessage,
+              (std::unique_ptr<PlatformMessage> message),
+              (override));
+  MOCK_METHOD(bool,
+              DoesHandlePlatformMessageOnPlatformThread,
+              (),
+              (const, override));
+  MOCK_METHOD(void,
+              InvokePlatformMessageResponseCallback,
+              (int response_id, std::unique_ptr<fml::Mapping> mapping),
+              (override));
+  MOCK_METHOD(void,
+              InvokePlatformMessageEmptyResponseCallback,
+              (int response_id),
+              (override));
+};
+
+// A class that can launch a RuntimeController with the specified
+// RuntimeDelegate.
+//
+// To use this class, contruct this class with Create, call LaunchRootIsolate,
+// and use the controller with ControllerTaskSync().
+class RuntimeControllerContext {
+ public:
+  using ControllerCallback = std::function<void(RuntimeController&)>;
+
+  [[nodiscard]] static std::unique_ptr<RuntimeControllerContext> Create(
+      Settings settings,                //
+      const TaskRunners& task_runners,  //
+      RuntimeDelegate& client) {
+    auto [vm, isolate_snapshot] = Shell::InferVmInitDataFromSettings(settings);
+    FML_CHECK(vm) << "Must be able to initialize the VM.";
+    // Construct the class with `new` because `make_unique` has no access to the
+    // private constructor.
+    RuntimeControllerContext* raw_pointer = new RuntimeControllerContext(
+        settings, task_runners, client, std::move(vm), isolate_snapshot);
+    return std::unique_ptr<RuntimeControllerContext>(raw_pointer);
+  }
+
+  ~RuntimeControllerContext() {
+    PostSync(task_runners_.GetUITaskRunner(),
+             [&]() { runtime_controller_.reset(); });
+  }
+
+  // Launch the root isolate. The post_launch callback will be executed in the
+  // same UI task, which can be used to create initial views.
+  void LaunchRootIsolate(RunConfiguration& configuration,
+                         ControllerCallback post_launch) {
+    PostSync(task_runners_.GetUITaskRunner(), [&]() {
+      bool launch_success = runtime_controller_->LaunchRootIsolate(
+          settings_,                                  //
+          []() {},                                    //
+          configuration.GetEntrypoint(),              //
+          configuration.GetEntrypointLibrary(),       //
+          configuration.GetEntrypointArgs(),          //
+          configuration.TakeIsolateConfiguration());  //
+      ASSERT_TRUE(launch_success);
+      post_launch(*runtime_controller_);
+    });
+  }
+
+  // Run a task that operates the RuntimeController on the UI thread, and wait
+  // for the task to end.
+  void ControllerTaskSync(ControllerCallback task) {
+    ASSERT_TRUE(runtime_controller_);
+    ASSERT_TRUE(task);
+    PostSync(task_runners_.GetUITaskRunner(),
+             [&]() { task(*runtime_controller_); });
+  }
+
+ private:
+  RuntimeControllerContext(const Settings& settings,
+                           const TaskRunners& task_runners,
+                           RuntimeDelegate& client,
+                           DartVMRef vm,
+                           fml::RefPtr<const DartSnapshot> isolate_snapshot)
+      : settings_(settings),
+        task_runners_(task_runners),
+        isolate_snapshot_(std::move(isolate_snapshot)),
+        vm_(std::move(vm)),
+        runtime_controller_(std::make_unique<RuntimeController>(
+            client,
+            &vm_,
+            std::move(isolate_snapshot_),
+            settings.idle_notification_callback,  // idle notification callback
+            flutter::PlatformData(),              // platform data
+            settings.isolate_create_callback,     // isolate create callback
+            settings.isolate_shutdown_callback,   // isolate shutdown callback
+            settings.persistent_isolate_data,     // persistent isolate data
+            UIDartState::Context{task_runners})) {}
+
+  Settings settings_;
+  TaskRunners task_runners_;
+  fml::RefPtr<const DartSnapshot> isolate_snapshot_;
+  DartVMRef vm_;
+  std::unique_ptr<RuntimeController> runtime_controller_;
+};
+}  // namespace
+
 namespace testing {
 
 class PlatformConfigurationTest : public ShellTest {};

runtime/dart_vm.cc

@@ -219,22 +219,22 @@ static std::vector<const char*> ProfilingFlags(bool enable_profiling) {
   // flags.
   if (enable_profiling) {
     return {
-      // This is the default. But just be explicit.
-      "--profiler",
-          // This instructs the profiler to walk C++ frames, and to include
-          // them in the profile.
-          "--profile-vm",
+        // This is the default. But just be explicit.
+        "--profiler",
+        // This instructs the profiler to walk C++ frames, and to include
+        // them in the profile.
+        "--profile-vm",
 #if FML_OS_IOS && FML_ARCH_CPU_ARM_FAMILY && FML_ARCH_CPU_ARMEL
-          // Set the profiler interrupt period to 500Hz instead of the
-          // default 1000Hz on 32-bit iOS devices to reduce average and worst
-          // case frame build times.
-          //
-          // Note: profile_period is time in microseconds between sampling
-          // events, not frequency. Frequency is calculated 1/period (or
-          // 1,000,000 / 2,000 -> 500Hz in this case).
-          "--profile_period=2000",
+        // Set the profiler interrupt period to 500Hz instead of the
+        // default 1000Hz on 32-bit iOS devices to reduce average and worst
+        // case frame build times.
+        //
+        // Note: profile_period is time in microseconds between sampling
+        // events, not frequency. Frequency is calculated 1/period (or
+        // 1,000,000 / 2,000 -> 500Hz in this case).
+        "--profile_period=2000",
 #else
-          "--profile_period=1000",
+        "--profile_period=1000",
 #endif  // FML_OS_IOS && FML_ARCH_CPU_ARM_FAMILY && FML_ARCH_CPU_ARMEL
     };
   } else {